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[Leon Novello]

Don`t worry about the maths, you are not alone, 7/4 of people can`t understand percentages.

[PeteF]

I eem to have posted a reply to a totally different three here!
Nurse!

[PeteF]

I eem to have posted a reply to a totally different three here!
Nurse!

[PeteF]

I eem to have posted a reply to a totally different three here!
Nurse!

[PeteF]

I eem to have posted a reply to a totally different three here!
Nurse!

[PeteF]

Oh blimey, what's going on?

[Exile]

Pete's off his meds again...

[Leon Novello]

MATRON! Pete`s out of his bed again.

[Exile]

I couldn't resist having a crack at this one..

Let me explain my thoughts here. We have some fixed points in this. The drive gear, driven gear and speed are fixed. Revs are variable.

Revs divided by speed divided by ratio will give a reference. The idea is to adjust the revs in relation to the ratio to give a constant 'reference'.

Below is the result of my extensive calculations...










Drive
Driven
Ratio
Revs
Speed
Reference


15
42
2,80
6000
60
35,714


15
40
2,67
5714
60
35,713


15
39
2,60
5572
60
35,718







So going down 3 teeth on the driven gear will give result of 5572 revs to maintain a speed of 60 mph.

[Exile]

Of course, another way to tackle this is to increase the number of teeth on
the drive gear.

Using the same model as above but changing the drive gear values give the
following results:







Drive
Driven
Ratio
Revs
Speed
Reference


15
42
2,80
6000
60
35,714


16
42
2,63
5625
60
35,714


17
42
2,47
5294
60
35,713


So, increasing the drive gear by one tooth would bring the revs down to 5625
to maintain the speed.



Just a thought....